Exercises: Triangle Congruence Criteria from Rigid Motions

Work through each section in order. For explanation problems, use complete sentences and reference rigid motions where relevant.

Grade 9·21 problems·~30 min·Common Core Math - HS Geometry·standard·hsg-co-b-8

Work through problems with immediate feedback

Warm-Up: Review What You Know

These problems review prerequisite skills from CO.B.6, CO.B.7, and Grade 8 geometry.

CPCTC stands for "Corresponding Parts of Congruent Triangles are Congruent." In a geometric proof, CPCTC is used:

As a reason to establish that two triangles are congruent.

After congruence has been established, to conclude that specific pairs of sides or angles are equal.

To prove that a triangle is isosceles.

As a substitute for identifying which congruence criterion applies.